Deformation characteristics of nanolayered dual-phase CrCoNi medium-entropy alloy nanowires

Due to the potential excellent mechanical properties of multicomponent alloys, the design of their microstructures and deformation mechanisms have attracted considerable attention. In this work, using molecular dynamics simulations, the mechanical behaviors of nanolayered face-centered cube/hexagonal close-packed (FCC/HCP) dual-phase CrCoNi medium-entropy alloys (MEAs) were investigated. The mechanical behaviors of the nanolayered dual-phase nanowires with various radii were studied and the effects of nanolayered dual-phase structure were evaluated. It was found that there are two different deformation modes mainly related to the dislocation nucleation position in the FCC phase or the HCP phase, of which in Model I dislocations nucleate from the intersection of phase boundary and surface, while in Model II dislocations nucleate on the surface of HCP phase. The deformation mode and strength change periodically with the variation of the surface disorder degree against radius. Annealing in the temperature range of 600–800 K can optimize the dual-phase structure, change the deformation mode and improve the mechanical performance.